Eyes everywhere: Devices that collect data

A guide to consumer devices and services, and the types of data they collect.

•PERSONAL COMPUTERS

Web browsers create records of sites you've visited.

Google, Bing and other search engines can record the types of searches you're performing, sometimes keeping them for many years.

Commerce websites like Amazon.com often keep detailed records of past purchases to be able to recommend items you might like.

Many online advertisements, when clicked, make a note of the types of products you might be likely to buy.

Social networking sites like Facebook record usage patterns such as the photos you've looked at and whose profile you've viewed.

•CELLPHONES

Smartphones record your location as you move around, both to find you when you have an incoming call and to offer map-based services such as driving routes and lists of restaurants that are near you.

Applications — or apps — can transmit many of the same types of data that personal computers can, including information gleaned from Web search, social networking and online purchases.

•TV SET-TOP BOXES

The box you get from your cable provider, or that you buy from companies such as TiVo, logs the shows you watch, which commercials you fast-forward through and, in some cases, when you mute the TV or change the channel.

•CUSTOMER LOYALTY CARDS

The plastic cards you get at Ralphs, Vons, Target and many other stores enable merchants to record the items you've purchased and market to you based on what a person like you may be most likely to buy in the future.